Silicon single crystal pull-up apparatus that pulls a doped silicon single crystal from a melt

Abstract

A silicon single crystal pull-up apparatus includes a pull-up furnace, a sample chamber in which a sublimable dopant is housed, a sample tube which can be raised and lowered between the interior of the sample chamber and the interior of the pull-up furnace, a raising and lowering means for raising and lowering the sample tube, a supply pipe which is installed inside the pull-up furnace and supplies the sublimable dopant to a melt, and a connection means for connecting the sample tube and the supply pipe. The connection means is constructed from a ball joint structure comprising a convex member which projects from one end of the sample tube and a concave member which is provided at one end of the supply pipe and is formed to be engageable with the convex member. The contact surfaces of the convex member and the concave member are formed to be curved surfaces.

The invention claimed is: 
     
       1. A silicon single crystal pull-up apparatus that pulls a doped silicon single crystal from a melt by Czochralski method, the apparatus comprising:
 a pulling furnace; 
 a sample chamber that is externally attached to the pulling furnace and houses a sublimable dopant; 
 a sample tube that can move up and down between an inside of the sample chamber and an inside of the pulling furnace; 
 an elevation/descent means that moves the sample tube up and down; 
 a supply pipe that is provided inside the pulling furnace and supplies the sublimable dopant discharged from the sample tube to the melt; and 
 a joint means that joins the sample tube with the supply pipe, 
 wherein the joint means is composed of a convex portion that projects from a first end of the sample tube and a concave portion that is provided in a first end of the supply pipe and formed such that the convex portion can fit thereinto; 
 the joint means is configured in a ball joint structure in which contacting surfaces of the convex portion and the concave portion are formed to be curved surfaces and the convex portion fits into and is joined with the concave portion; and 
 a flow path is formed between the sample tube and the supply pipe. 
 
     
     
       2. A silicon single crystal pull-up apparatus that pulls a doped silicon single crystal from a melt by Czochralski method, the apparatus comprising:
 a pulling furnace; 
 a sample chamber that is externally attached to the pulling furnace and houses a sublimable dopant; 
 a sample tube that can move up and down between an inside of the sample chamber and an inside of the pulling furnace; and 
 an elevation/descent means that moves the sample tube up and down; 
 a supply pipe that is provided inside the pulling furnace and supplies the sublimable dopant discharged from the sample tube to the melt; and 
 a joint means that joins the sample tube with the supply pipe, 
 wherein the joint means is composed of a concave portion that is provided in a first end of the sample tube and a convex portion that is provided in a first end of the supply pipe and formed such that the concave portion can fit thereonto; 
 the joint means is configured in a ball joint structure in which contacting surfaces of the concave portion and the convex portion are formed to be curved surfaces and the concave portion fits onto and is joined with the convex portion; and 
 a flow path is formed between the sample tube and the supply pipe. 
 
     
     
       3. The silicon single crystal pull-up apparatus according to  claim 1 ,
 wherein an outer surface of the convex portion has a substantially spherical shape and an inner surface of the concave portion has a curved shape that corresponds to the outer surface of the convex portion. 
 
     
     
       4. The silicon single crystal pull-up apparatus according to  claim 1 ,
 wherein the elevation/descent means is provided with a guide rail on which the sample tube can slide; and 
 the sample tube is guided by the guide rail and fits the convex portion into the concave portion. 
 
     
     
       5. The silicon single crystal pull-up apparatus according to  claim 1 ,
 wherein the sublimable dopant is arsenic or red phosphorus.